Excavator

ABSTRACT

An improved excavator which is provided with a transmitter, a receiver and antennae of a buried metal detector, being characterized in that said antennae comprise three antennae which are disposed in the bucket arm of said excavator in three dimensional perpendicular relation, and thereby the damages of buried metal facilities can be prevented.

United States Patent [191 Appl. No.: 309,888

Foreign Application Priority Data Field of Search 214/761, 762, 764;324/41 324/67; 37/DlG. 19; 56/102, D16. 15

References Cited UNITED STATES PATENTS Maust 37/D1G. l9

[111 3,858,737 Senoo 3 1 1 Jan. 7, 1975 [5 EXCAVATOR 2,409,397 l0/l946Sheehan r. 37/DlG, 19 [76] Inventor: Rikizo Senoo, 2-14, Nihombashifiggfigfff Kakigara-cho, Chuo-ku, Tokyo,

Japan Primary ExamtnerRobert J. Spar i 1 Fllfidi 1972 AssistantExaminer-John Mannix Attorney, Agent, or FirmLerner, David, Littenberg &Samuel [57] ABSTRACT An improved excavator which is provided with atransmitter, a receiver and antennae of a buried metal detector, beingcharacterized in that said antennae comprise three antennae which aredisposed in the bucket arm of said excavator in three dimensionalperpendicular relation. and thereby the damages of buried metalfacilities can be prevented.

3 Claims, 6 Drawing Figures PATENTED JAN 7 5 SHEEF 2 OF 2 mumSsw mwk 0QEXCAVATOR FIELD OF THE INVENTION The present invention relates to animproved excavator for digging the soil. Further, the invention relatesto the excavator which is provided with a transmitter, a receiver andantennae of a buried metal detector being characterized in that saidantennae comprise three antennae and positioned in the bucket arm of theexcavator in three dimensional perpendicular relation. Still further,the invention relates to the excavator which can detect the buried metalfacilities to stop the bucket arm thereof.

BACKGROUND OF THE INVENTION Excavators are generally employed fordigging the soil in construction site, and if the public facilities suchas city-water pipes, gas pipes, electricity cables and telephone cablesare buried in the ground, these facilities are liable to be damaged bythe digging bucket of the excavator during the construction work. Andwhen these accidents are brought about, the dwellers in theneighbourhood are caused several troubles such as failures of watersupply and power supply, and inundation, in addition to that they incurthe damage of their lives by the accident such as explosion of thecity-gas.

Therefore, the object of the invention is to prevent such accidents andtroubles from occurring. Further object of the invention is to provide anovel excavator which can proceed the digging work without causing suchaccidents and troubles, i.e. the damages of water pipes, gas pipes,electricity cables and telephone cables.

BRIEF SUMMARY OF THE INVENTION Pursuant to the above objects, thepresent invention proposes an improved excavator which is provided witha transmitter, a receiver and antennae of a buried metal detector, inwhich said antennae comprise three antennae attached to the bucket armportion of the excavator, and is disposed in three dimensionalperpendicular relation with each other. Further, the receiver asprovided can be interlocked to the driving source of the bucket arm,thereby when the signal form a buried metal article is detected, thework of the bucket is immediately stopped to prevent the damage of saidarticle.

BRIEF DESCRIPTION OF THE DRAWINGS These and other feature of theinvention will be more fully understood by referring to the followingdetailed description presented solely for the purpose of illustrationand to the accompanying drawings in which:

FIG. 1 is a schematic illustration of the use of the excavator;

FIG. 2 is a plan view of the bucket in which the antennae are diposedaccording to the invention;

FIGS. 3, 4 and 5 are diagrams showing the characteristics of the buriedmetal detector and FIG. 6 shows the interlocking of the power source ofthe excavator of FIG. 1 with a receiver in accordance with one aspect ofthis invention.

DETAILED DESCRIPTION OF THE INVENTION Now referring to the drawings, theexcavator of the present invention will be explained. In the drawings,

the numeral 1 indicates a back hoe, the numeral 2 is a digging arm ofthe back hoe 1, and the numerals 3, 4 and 5 are bar antennae. As shownin FIG. 2, the bar antennae 3, 4 and 5 are disposed adjacently to thebucket 6 of the digging arm 2 in three dimensional arrangementimaliifih'r, i.e., in the perpendicular relations. The numeral 7 is atransmitter of a buried metal detector and the numeral 8 is a receiver,both of which are installed within the back hoe 1. Further, the numeral9 indicates a buried metal pipe.

The transmitter 7 and the receiver 8 of the buried metal detector whichare employed in the device of the present invention, have respectiveloop coils. In general, when these loop coils are positioned on theground perpendicularly, the directivity of the electromagnetic waveshows the figure 8 characteristic as shown in FIG. 3. Accordingly, theintensity of the electromagnetic wave is most strong in the direction ofA A, and in other directions, for example, in the directions of B and C,the intensity decreases gradually, and at last the intensity of theelectromagnetic wave becomes the minimum.

Thus, when the transmitter 7 is put up on the ground, theelectromagnetic wave is radiated into the ground, and if a metallicarticle such as a metal pipe or cable is buried in the ground, theelectromagnetic'field is induced by said metallic article as shown inFIG. 4. The intensity of this electromagnetic wave becomes larger, ifthe metallic article is buried in a shallow place, or the metallicarticle is large or the direction of the metallic article is parallel tothe face of the coil. While, if the direction of the metallic article isinclined to the face of the coil in like manner as the arrow B or C inFIG. 3, the intensity of the electromagnetic wave is reduced as much. Incase a receiver is placed in the electromagnetic field thus induced,several receiver sensitivities will be obtained according to theposition of the receiver. As indicated in FIG. 5, if the receiver 8 ispositioned in the magnetic field of the electromagnetic wave 10 which isinduced by the transmitter 7, the receiver sensitivity is largest in theposition E, it is decreased in some degree in the position F, and it isthe minimum in the position G. And the farther the receiver is movedaway, the smaller the receiver sensitivity becomes, as indicated by themark H.

The buried metal detector has the above-mentioned characteristic, thusthe transmitter is placed previously just above the buried metal pipe inadjacent to the construction site, in which the loop coil of thetransmitter is disposed in paralles with the buried metal 9, thereby theelectromagnetic field is produced on the buried metallic pipe 9.Accordingly, if the aforementioned back hoe 1 get near the buried pipe9, the pipe 9 in any direction can be detected by the set of threeantennae 3, 4 and 5 which are attached on the digging arm 2 of the backhoe l in three perpendicular directions. In the meantime, byinterlocking the receiver 8 with the power source 11 of the back hoe 1,via lead 12 (see FIG. 6) the latter can be totally stopped just upon thedetection of the buried metallic pipe 9 by said antennae. Further, thedistance between the buried pipe 9 and the top portion of the bucket 6of the back hoe I in which the back hoe l is to be stopped, can beregulated by adjusting the sensitivity of the receiver 3.

Thus if the device of the present invention is used in the excavationwork, the buried pipe 9 is never caused damage because the back hoe 1can be stopped immediately on the detection of the pipe 9 by theantennae 3, 4 and 5. Therefore, the device of the present invention isvery effective and advantageous in the construction site.

Further, in order to turn back the stopped bucket 6 of the back hoe l,the conventional electromagnetic relay can be used according to wellknown manner.

It should be emphasized, however, that the specific embodimentsdescribed and shown herein are intended as merely illustrative and in noway restrictive of the invention.

What is claimed is:

1. An excavator having a bucket arm and which is when a signal isreceived by said receiver.

1. Ajn excavator having a bucket arm and which is provided with a buriedmetal detector including a transmitter, a receiver and an antennae, inwhich said antennae comprises three elements; said three elements beingpositioned on said bucket arm of said excavator and are disposed inthree-dimensional mutually perpendicular relationship with each other.2. An excavator as defined in claim 1 in which said three elements arebar antennae.
 3. An excavator as defined in claim 1 also including:means for interlocking said receiver to the driving source of saidbucket arm to stop said bucket arm when a signal is received by saidreceiver.